System temperatures and noise levels were recorded with SpeedFan and GPU-Z
at idle and on load using Prime95 (large FFTs setting) and FurMark, an OpenGL
benchmarking and stability testing utility.

Stock Fan Noise

The 120 mm exhaust fan.

The Define R3 had different fans than the R2 with higher speeds (1350 RPM vs. 1000 RPM) and different blade design, and they've switched it up once again with the Define Mini. The two included fans inexplicably have the same model number as the old ones (FD-FAN-120) but are 150 RPM slower and have 11 blades rather than 7.

Baseline Noise Level

Fan Voltage

Front

Rear

Combined

12V

21~22 dBA

25 dBA

26~27 dBA

9V

17 dBA

20 dBA

21~22 dBA

7V

14 dBA

16 dBA

17~18 dBA

5V

11~12 dBA

12 dBA

13 dBA

Measuring mic positioned 1m at diagonal angle left/front
of case.

The new fans have a similar acoustic character, being quite smooth at any speed, but we noticed the front model had a noticeable clicking noise. This might be because it was mounted to a plastic frame, which in turn was clipped onto the case. The fan controller can be adjusted from 12V down below 4V, until the fans stop spinning completely. Altogether, they produced 26~27 dBA@1m at full speed and were close to inaudible at 5V. This wide range makes the fans and the controller versatile enough to complement gear with varying levels of noise.

The sweet spot for the stock fans was 7V where they measured 17~18 dBA@1m inside the case.